Tuesday, 5 November 2013

WHY IS MARS RED?

Mars is often referred to as the red planet but is it really red, and if so why?

Mars is the forth planet from the sun, next to Earth. However it is much further away from the sun then our planet and so it is very cold with an average temperature of minus 63 Celsius. The atmosphere is 100 times thinner than here on Earth and consists of mostly carbon dioxide. Violent dust storms rage across the planet and often obscure mars from our view.

Mars appears in the sky as an orange-red star. The orange effect is due to the rock formation of the planet. Space craft landing on Mars have collected rock samples which reveal that Iron oxide (rust) is present in the rocks, giving an orange hue to the planet. The iron oxide would have formed in the past when water was present on the surface, and has been deposited across the surface of the planet by dust clouds. If you dig down a few just below the surface the soil is brown in colour similar to ours. The red colour can vary from location to location, sometimes being vivid orange, red or even black.

The sky on mars is also red, due to the scattering of red photons by dust particles in the atmosphere. However sunsets on mars are blue as the dust absorbs the red particles revealing more of the blue photons from the sun.